bp

Binary patcher. Takes asm and C as inputs.

Vibe-coded with GPT-5.3 Codex.

Usage

bp prepare generates a patch, and bp apply applies the patch.

The following demo will generate a.out.patch. The original one prints "Hello, World!\n" whereas the patched one doesn't.

0. Write patch in asm or C

$ cat example/patch.c
@foo
void newfoo()
{
    return;
}

Note that @ indicates the address to be patched. It can be a symbol and immediate address.
This simply replaces the target address with the patch contents.

1. Prepare patch

$ ./bp prepare example/patch.c -o patch.elf -t example/a.out

This aggregates multiple patches and generates one patch.elf. objdump -d patch.elf will show the patch plan, including the addresses to be patched, and the contents.

2. Apply patch

./bp apply -p patch.elf -i ./example/a.out -o a.out.patch

Done.